Abstract: Optical switching devices for use in photonics applications are created in a body of an optically transparent defocusing material having a third order non-linear susceptibility which is negative. The switching devices use optical waveguides which are created by the propagation through the material of dark spatial solitons, which are induced when an intense quasi-planar light wave, having an amplitude or phase perturbation to at least one point or region of its wavefront, is projected onto at least one location on the surface of the body, to cause a change in its refractive index at the (or each) location. If the change in refractive index is rapid and transitory, an active photonic device is created. The devices created include steerable optical switches, cross-couplers, and multi-port optical switchyards.